The present invention relates to an external bone fixator and more particularly to an external bone fixator that is selectively a bridging and non-bridging fixator.
It is known in the art that bones should be fixed or aligned in a particular position or orientation after an injury and several different methods are used. One generally known method is to place a cast on the injured area using a material that hardens after application, such as a plaster cast. The use of such a plaster cast, however, generally completely immobilizes the portion of the anatomy about which it is placed. Additionally, such plaster casts are extremely large and bulky and can be rather heavy for a patient who must use the plaster cast.
Additional bone fixation devices known in the art include internal fixation plates or external fixators. Attachment devices, such as screws or pins, affix the plate fixators to the bone sections which must be held in place and fixed during the healing process. These internal plates and external fixators are generally of an unitary length and of a fixed construction not allowing any motion of the anatomy to which it is attached while it is in place throughout the entire healing process.
Additionally, bone fixation pins and screws, and other internal devices, that are simply lodged into a bone structure may also be used to hold a bone in a fixed position while it is healing. These devices ensure that the bone is held in the proper position during healing without permitting further trauma to the bone. Here again, the internal pins and screws also do not allow movement of the fixed or attached portions of anatomy once inserted.
Accordingly, most of these devices create complete immobility in the portion of the anatomy upon which they are placed during the recovery process. This complete immobilization of a portion of anatomy, especially when it is a joint or other moving part, can stiffen and injure the joint due to non-movement. Additionally, adjacent portions of the anatomy are often used to support the part which is healing, thereby immobilizing greater sections of the anatomy. In particular, if an arm or wrist injury occurs and a bone must be fixed during the recovery period, the loss of motion in the joint may increase pain and the possibility of injury after the fixation device has been removed. Therefore, it is desirable to have a fixation device which will allow some movement during a portion of the recovery process, while also ensuring proper immobilization of the body portion under recovery so that corrective healing may occur.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
The present invention relates to a convertible external bone fixator that converts between a bridging and non-bridging operation. The external bone fixator is made to fix bones relative to each other across a joint and then later allow movement of the joint by removing a first portion of the external bone fixator. The conversion from bridging to non-bridging operation is accomplished without detaching a second portion of the bridging/non-bridging bone fixation device.
A first embodiment includes an external bone fixation device for fixing a first bone and a second bone relative to one another in a predetermined orientation. The external bone fixation device includes a first bone fixation member that has a tail portion and a head portion each defining a plurality of bores and extending only along a portion of the length of the first bone. A connector extends from the first bone fixation member. A second bone fixation member has a proximal end and a distal end, wherein the proximal end is selectively affixed to the connector. A first selective attachment device selectively affixes the first bone fixation member to the first bone. A second selective attachment device selectively affixes the second bone fixation member to the second bone. When the first bone fixation member is selectively affixed to the first bone and the second bone fixation member is selectively affixed to both the connector and the second bone the first and second bones are substantially immobile.
A second embodiment of the present invention includes an external bone fixation device for fixing an arm bone, a wrist bone, and a metacarpal in a predetermined orientation. The external bone fixation device includes a first rigid bone fixation member, having a proximal tail portion and a distal head portion, defining a plurality of bores through said tail portion and said head portion. A holding mechanism extends from the distal head portion. A second bone fixation member selectively interconnects the holding mechanism and the metacarpal. A first attachment device selectively affixes the first bone fixation member to the arm bone. A second attachment device selectively affixes the second bone fixation member to the metacarpal. When the first bone fixation member is affixed to the arm bone and the second bone fixation member is selectively interconnected between said holding mechanism and the metacarpal, then the metacarpal is substantially immobile.
A third embodiment of the present invention includes an external bone fixation device for fixing an arm bone, a wrist bone, or a metacarpal in a predetermined orientation. The external bone fixation device includes a first rigid bone fixation member, having a proximal tail portion and a distal head portion having a side. The proximal tail portion defines a first plurality of bores formed longitudinally along said tail portion. The distal head portion defines a second plurality of bores in an array thereon, wherein at least a portion of the second plurality of bores are displaced laterally from the first plurality of bores. A mounting body extends from the side of the distal head portion. The second bone fixation member has a proximal end and a distal end, wherein a portion of the proximal end is received in said mounting body, and is selectively affixed in the mounting body. A first attachment device affixes the first bone fixation member to the arm bone. A second attachment device selectively affixes the second bone fixation member to the metacarpal. When the first bone fixation member is affixed to the arm bone and the second bone fixation member is selectively affixed to the metacarpal, and the second bone fixation member is selectively affixed in the clamp then the wrist and metacarpal are substantially immobile.